New Delhi’s latest bid to combat suffocating winter smog kicked off with a Cessna aircraft lifting off from Kanpur on Tuesday, dispersing flares loaded with sodium iodide and sodium chloride over targeted zones in the capital. This marks the start of a multi-day cloud-seeding experiment, spearheaded by the Delhi government in partnership with IIT Kanpur, aimed at triggering artificial rainfall to flush out airborne toxins.
The intervention comes amid a sharp deterioration in air quality across the National Capital Region, where readings have hovered in the “very-poor” bracket for the past week. According to a nationwide monitoring network, the city’s average PM2.5 levels—fine particulate matter measuring 2.5 microns—reached 136 micrograms per cubic metre by 7pm Tuesday, exceeding the World Health Organisation’s safe threshold of 15 micrograms per cubic metre by a factor of nine.
Delhi Environment Minister Manjinder Singh Sirsa hailed the effort as “a huge step… to mitigate pollution,” pledging in a PTI report that successful outcomes could pave the way for a sustained strategy. Earlier this year, the government greenlit ₹3.2 crore for these trials, formalizing an agreement with IIT Kanpur last month to focus operations northwest of the city, as per PTI.
Yet, as of late Tuesday, the India Meteorological Department reported no precipitation in Delhi, echoing a prior test flight over north Delhi last week that fizzled due to insufficient atmospheric moisture—below 20 per cent, far short of the 50 per cent benchmark typically needed for viable seeding.
Weather experts are voicing reservations, arguing the push reflects political urgency more than scientific rigor. “Scientists familiar with cloud-seeding research say the failed test raises questions about whether the trials are considering key quantitative criteria such as cloud moisture, temperature and updraft wind,” noted The Telegraph.
These concerns draw from rigorous prior studies, including the world’s largest randomized cloud-seeding experiment run by the Indian Institute of Tropical Meteorology (IITM) in Pune from 2018-2019. That trial analyzed 151 seeded clouds against 125 unseeded ones, yielding an average 18 per cent rainfall boost, according to Thara Prabhakaran, the IITM lead scientist who spoke to The Telegraph.
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Internationally, nations like China, South Korea, and Pakistan have deployed similar tactics against pollution, but outcomes remain patchy. Madhavan Rajeevan, a veteran atmospheric physicist and ex-secretary of the Union earth sciences department, dismissed it outright: “This is not a viable solution to air pollution. Even if there is some induced rain, it’s unclear how long its effect will last in the continued presence of the pollution sources—the real solution lies in finding ways to reduce or curb the pollution.”
No domestic research has yet quantified cloud seeding’s impact on pollution levels or its duration, two Indian scientists versed in the field told The Telegraph. An IIT Kanpur faculty member, who in a December 2023 PTI interview touted a “novel seeding solution of salts” developed by the institute, did not respond to queries on Tuesday’s results or expert critiques. Research indicates any induced rain should materialize 30 minutes to three hours post-seeding.
The government’s air quality forecast offers little relief, projecting “very poor” conditions through October 31, with fluctuations between “poor” and “very poor” over the ensuing week.
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